1. Field of the Invention
The present invention relates to a mounting structure of a flexible inductor that connects two circuits and an electronic device that includes the mounting structure.
2. Description of the Related Art
In the related art, an electronic device that uses a high-frequency signal often employs a structure in which the electronic device includes members of a mounting circuit, such as a plurality of substrates, in a housing of the electronic device, and in which the members are connected by flexible cables. In addition, there is a case where a planar coil-shaped conductive pattern is provided as a portion of a flexible cable as disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2011-18505.
For example, in a small-sized communication terminal device, metallic objects, such as a ground conductor, a battery pack, and a shield case, are densely mounted. When a cable that includes a coil-shaped conductive pattern is mounted in such a small-sized electronic device, metallic parts (metallic objects) are forced to be positioned in the vicinity of the coil-shaped conductive pattern. As a result, an eddy current is generated in the metallic parts, and accordingly, the Q value of an inductor is decreased.
The influence of the metallic parts, which are positioned in the vicinity of the coil-shaped conductive pattern, can be reduced to a minimum value by forming a closed magnetic circuit structure by covering the coil-shaped conductive pattern with a magnetic material, such as ferrite, like the flexible cable described in Japanese Unexamined Patent Application Publication No. 2011-18505.
However, in the case of such a structure that includes a magnetic material, management and manufacturing processes for adding the magnetic material become complex, and in addition, the size of a flexible cable, which would have been thin, becomes large. In addition, in the case where a ceramic-based ferrite is used as the magnetic material, the flexibility of the flexible cable is degraded.